2-(6-硝基-2-苯并噻唑偶氮)-5-二甲氨基苯甲酸与铜显色反应的研究及应用

Colour Reaction of 2-(6-Nitro-2-benzothiazolylazo)-5-dimethylaminobenzoic Acid With Copper and Its Application

本文研究了2-(6-硝基-2-苯并噻唑偶氮)-5-二甲氨基苯甲酸(6-NO_2-BTAMB)与铜的显色反应。结果表明,在pH2.0～4.5的乙醇水溶液中6-NO_2-BTAMB与铜形成一种稳定的蓝绿色络合物,其最大吸收波长位于650nm处,表观摩尔吸收系数为7.75×10~4L·mol^(-1)·cm^(-1),络合物的组成为6-NO_2·BTAMB:Cu=1:1,铜浓度在0～10μg/10ml范围内服从比尔定律。该方法具有良好的选择性和灵敏度。在氟化铵和硫脲存在下,利用差减法,可直接测定含微量镍和钴的镁、铝合金中的铜,结果满意。

The condition for the colour reaction of 2-( 6-nitro-2-benzothiazolylazo )-5-dimethylaminobenzoic acid(6-NO_2-BTAMB) with copper has been studied. The experimental results show that copper reacts with 6-NO_2-BTAMB to form a stable blue complex at pH 2.0-4.5. The apparent molar absorptivity is 7.75×104 L ·mol^(-1) ·cm^(-1) in aqueous ethanol solution at 650 nm. Beer's law is obeyed in the range of 0-10 μg/10 ml for copper. The ratio of copper to 6-NO_2-BTAMB in the complex is 1 : 1. The proposed method has been applied to the spectrophotometric determination of trace copper in aluminium and magnesium alloys with satisfactory tesults.